Free and Excluded Multimeters

While we’re reviewing multimeters, let’s take a look at the cheapest meter you can ever hope to obtain, a free meter included with an order.
And, let’s look at two other types of meters that aren’t included in the multimeter shootout tests because they aren’t designed for the same purposes as the other meters.

Free Meter

Circuit Specialists Web Tronics give-away digital multimeter.

The least expensive meter being tested is the one I got for free from Circuit Specialists with a $100 order many years ago.
This is a manual ranging meter with the most basic features.
But, it does have a thick rubber covering, decent jacks, a stand, continuity buzzer, and can test white LEDs.

It is being included in the multimeter tests not because you can buy one, but to see if the very cheapest meters are accurate.

Excluded Meters

There are a couple of types of meter that are not part of the multimeter tests because they were designed for other purposes.

Amp Meter

Do not buy a clamp meter for most hobbyist work.

This type of meter is used for residential and commercial electricians, not digital robot building hobbyists.
The hook shape is for measuring AC current without cutting the wire.

These meters are not designed for low voltage DC measurements.
If you insist on using one, you'll be disappointed in the lack of features and the lack of a low range.

This isn’t a bad meter; just inappropriate for this use.

SparkFun Multimeter Kit

SparkFun Multimeter Kit.

The SparkFun Electronics digital meter (KIT-09573) is a kit that is available for $19.95, not including shipping.
It is an autoranging meter that focuses on a few basic measurements: DC voltage, DC current, resistance, and continuity (buzzer).

This meter has some exclusive features:

Bright numeric LEDs instead of an LCD

Displays values up to 9999, instead of only 1999 or 3999

The schematic and source code are posted online, so you can customize the programming.
It was particularly cool of SparkFun Electronics to include an ATmega328, rather than a lesser 48, 88, or 168, since the 328 has 32KB of programming space.

However, being a kit and being inexpensive, it also has limitations:

You assemble and solder it yourself

Lacks certain measurements (AC, diode, capacitance, transistor)

Narrow range of voltage and current

Limited protection against overvoltage and overcurrent

You can’t reverse the probes for voltage and current (doesn’t support negative values)

If they added parts to provide complete functionality, the cost and complexity of the kit would increase.

Fully sheathed banana plugs do not fit.

The kit has plated-through holes instead of jacks.
The holes only accept banana plugs with plastic shielding that does NOT extend the length of the plug.
Most test probes have the full plastic covering, thus limiting your choices of probes.

Avoid trimming off the plastic sheath of test probes that you already own, because the plastic exists for safety reasons.
The plastic helps prevent you from touching the metal banana plug when unplugging the multimeter end of the cable while the other end is connected to a power source.
This could happen when switching sockets for different measurement modes.

Programming connection behind LED display.

The SparkFun Electronics meter kit PCB includes holes for a standard ISP6 programming cable for the Atmel microcontroller.
Unfortunately, the other side of these holes is underneath the LED display.
If you solder the LED display before adding the pins (not included), you are going to have a really difficult time adding the pins later on.
But, if you do decide to add the pins, the board will no longer lay flat because the pins would be the only component on the underside.
Instead, if you own an Atmel programming board, add a socket to the MCU of the multimeter kit.
Then, you can remove the microcontroller for programming rather than using the ISP connection.

The kit could be improved with revised software, slightly adjusted PCB, and $1 worth of parts (ADC capacitor, MCU socket, better-tolerance resistors, and PTC resettable fuse).
But, as-is, this should be considered a fun exercise rather than a multimeter.
Therefore, I have excluded it from the test results of this article.

That covers the meters I had to choose from for the multimeter tests and review.
The next page describes the parts and circuits used to test the meters.